1. Field of the Invention
The present invention relates to a fluid coupling element, of the type comprising: a base body defining a central axis (X-X) of fit of an complementary fluid coupling element, a locking ring, movable relative to the base body, at least one locking ball that is capable of locking the complementary fluid coupling element relative to the base body, the or each locking ball being radially movable in the body between a locking position, wherein the locking ball is adapted to lock the complementary fluid coupling element, and an unlocking position wherein the locking ball frees the passage for the complementary fluid coupling element, at least one actuating ball of the locking ring adapted to be pushed into an elongated housing of the base body by the complementary fluid coupling element during the coupling of the coupling element and the complementary coupling element, so as to move the locking ring axially from a locking position, wherein the or each locking ball is locked in said locking position, at least into a release position in which the or each locking ball is free to move in said unlocking position for unlocking the means for returning the locking ring to said locking position.
It applies in particular to fluid couplings in the chemical or food industry.
2. Brief Discussion of the Related Art
A coupling assembly comprising such a coupling element is known from DE3023377. This document discloses a coupling with actuating ball (in the lower portion of FIGS. 1 and 2 of this document) accommodated in an elongated housing. Said balls pushed by the complementary coupling element I move the locking ring in such a way that the locking balls (in the upper portion of FIGS. 1 and 2 of this document) are able to engage in the element I for the locking thereof. It is clear that all the balls have the same diameter.
Another coupling assembly is known from the document EP2088360, which discloses a coupling in which the locking ball is also involved in the movement of the locking ring to the coupling and in which the angle α of the surface of the complementary coupling element 32a in contact with the actuating ball is greater than the angle β of the inclined surface 50a of the lock ring in contact with the actuating ball when the actuating ball moves the locking ring.
In both documents of the state of the art, given the low radial overruns of the actuating ball, of the same diameter as the locking ball, on each side of the body, and on account of the radial clearances of operation, it is not possible to ensure that the actuating ball is bearing against the conical surface as in 32a in EP2088360 and against the conical surface of the type 50a (in EP2088360) rather than on the fillets of these surfaces. Therefore it is not possible to ensure, despite α>β, that the actuating ball remains in engagement between the locking ring and the complementary coupling element without being driven radially outward during the recoil of the locking ring for the coupling.
Moreover, because of operating clearances and manufacturing tolerances, it is not excluded in DE3023377 that the locking ball has to actuate the locking ring for coupling, which would lead to very significant connection loads.